The long-term objective of this research project is an in-depth investigation of the kinetic, functional, structural, and thermodynamic properties of various chemically well-defined phospholipids in model membrane systems. Specifically, our experiments are designed along the following lines: (1) We have recently applied high-sensitivity differential scanning calorimetry, laser Raman spectroscopy, 31p- and 14N-NMR spectroscopy, ultracentrifugation, X-ray diffraction, together with generl bochemical techniques, to invetigate asymmetric mixed-chain phosphatidylcholine (PC) dispersions. We shall continue our investigation on the phase begavior, structure an dynamics of various PCs in which the sn-2 acyle chain is only half as long as the sn-1 acyl chain. These PCs are most likely to form mixed interdigitated bilayers at T(Tm. (2) We aim to study the kinetics of the metastable gel stable subgel transition. (3) We shall examine the polymorphic phase begavior, the structure, and dynamics of lysophosphatidy lethanolamine and its N-methyl derivatives. (4) We shall investigate the effects of mixed-chain phospholipide and diachylglycerols on the enzyme activity and kinetics of protein kinase C. (5) We shall develop a theoretical model to describe the phase tansition behavior of interdigitated bilayer. Information gained from this proposal will add a new dimension to our current knowledge about the structure, dynamics, and functions of membrane lipids.